mypy failure for Variable + Dataset arithmetic in test_typed_ops.py with Python 3.12 only

[shoyer]

What is your issue?

I get the following error when I run mypy in a Python 3.12 environment:

$ python -m mypy --install-types --non-interactive
xarray/tests/test_typed_ops.py: note: In function "test_dataset_typed_ops":
xarray/tests/test_typed_ops.py:139: error: Argument 1 to "_test" has incompatible type "Variable"; expected "Dataset"  [arg-type]
xarray/tests/test_typed_ops.py:140: error: Argument 1 to "_test" has incompatible type "DataArray"; expected "Dataset"  [arg-type]
xarray/tests/test_typed_ops.py:151: error: Argument 1 to "_test" has incompatible type "Variable"; expected "Dataset"  [arg-type]
xarray/tests/test_typed_ops.py:152: error: Argument 1 to "_test" has incompatible type "DataArray"; expected "Dataset"  [arg-type]
xarray/tests/test_typed_ops.py:163: error: Argument 1 to "_test" has incompatible type "Variable"; expected "Dataset"  [arg-type]
xarray/tests/test_typed_ops.py:164: error: Argument 1 to "_test" has incompatible type "DataArray"; expected "Dataset"  [arg-type]
Found 6 errors in 1 file (checked 167 source files)

When I run this using an identical Python 3.11 setup, mypy passes without any errors.

The offending lines are doing arithmetic operations like Variable + Dataset or DataArray + Dataset.

Enviroment details:

Python 3.12

commit: df87f69
python: 3.12.7 | packaged by conda-forge | (main, Oct 4 2024, 15:57:01) [Clang 17.0.6 ]
python-bits: 64
OS: Darwin
OS-release: 23.6.0
machine: arm64
processor: arm
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8
LOCALE: ('en_US', 'UTF-8')
libhdf5: 1.14.3
libnetcdf: 4.9.2

xarray: 2024.9.1.dev81+g994550f0
pandas: 2.2.3
numpy: 2.0.2
scipy: 1.14.1
netCDF4: 1.7.1
pydap: 3.5
h5netcdf: 1.4.0
h5py: 3.12.1
zarr: 2.18.3
cftime: 1.6.4
nc_time_axis: 1.4.1
iris: 3.9.0
bottleneck: 1.4.2
dask: 2024.10.0
distributed: 2024.10.0
matplotlib: 3.9.2
cartopy: 0.24.0
seaborn: 0.13.2
numbagg: 0.8.2
fsspec: 2024.9.0
cupy: None
pint: None
sparse: 0.15.4
flox: 0.9.12
numpy_groupies: 0.11.2
setuptools: 75.1.0
pip: 24.2
conda: None
pytest: 8.3.3
mypy: 1.11.2
IPython: None
sphinx: None

Python 3.11

commit: df87f69
python: 3.11.10 | packaged by conda-forge | (main, Oct 16 2024, 01:26:25) [Clang 17.0.6 ]
python-bits: 64
OS: Darwin
OS-release: 23.6.0
machine: arm64
processor: arm
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8
LOCALE: ('en_US', 'UTF-8')
libhdf5: 1.14.3
libnetcdf: 4.9.2

xarray: 2024.9.1.dev77+gdf87f692
pandas: 2.2.3
numpy: 2.0.2
scipy: 1.14.1
netCDF4: 1.7.1
pydap: 3.5
h5netcdf: 1.4.0
h5py: 3.12.1
zarr: 2.18.3
cftime: 1.6.4
nc_time_axis: 1.4.1
iris: 3.9.0
bottleneck: 1.4.2
dask: 2024.10.0
distributed: 2024.10.0
matplotlib: 3.9.2
cartopy: 0.24.0
seaborn: 0.13.2
numbagg: 0.8.2
fsspec: 2024.9.0
cupy: None
pint: None
sparse: 0.15.4
flox: 0.9.12
numpy_groupies: 0.11.2
setuptools: 75.1.0
pip: 24.2
conda: None
pytest: 8.3.3
mypy: 1.11.2
IPython: None
sphinx: None